CN-121978144-A - Method for eliminating black spots induced by electrolytic polishing preparation of EBSD metal sample

CN121978144ACN 121978144 ACN121978144 ACN 121978144ACN-121978144-A

Abstract

The invention discloses a method for eliminating black spots induced by electrolytic polishing of an EBSD metal sample, which comprises the steps of cutting a sample, cleaning, adopting a wire cutting machine to cut the sample, putting the sample into an ultrasonic cleaner to clean, drying, coarse grinding, adopting sand paper to remove a hardening layer generated by wire cutting on a metallographic grinder, fine grinding, adopting sand paper with different mesh numbers to sequentially wet grind the sample from low to high, covering scratches ground for the next time, coarse polishing, uniformly coating a first diamond polishing paste, polishing until only shallow scratches remain on the surface of the sample, fine polishing, uniformly coating a second diamond polishing paste until the second diamond polishing paste is in a mirror surface shape, preparing absolute ethyl alcohol and perchloric acid into electrolyte according to the sequence of addition, and finally carrying out electrolytic polishing.

Inventors

HUANG YU
CHEN ZHIAN
WANG XIANG
WANG JUN
LIU CHENG

Assignees

扬州大学

Dates

Publication Date: 20260505
Application Date: 20251215

Claims (7)

1. A method for eliminating black spots induced by electropolishing preparation of an EBSD metal sample, comprising the steps of: S1, cutting and cleaning a sample, namely cutting the sample by a wire cutting machine, cleaning the sample in an ultrasonic cleaner, and drying the sample; s2, rough grinding, namely removing a hardening layer generated by wire cutting on a metallographic grinder by adopting sand paper; s3, fine grinding, namely sequentially wet grinding the sample by adopting sand paper with different mesh numbers from low to high, wherein each grinding ensures that the sample rotates 90 degrees, and scratches of the later grinding are covered for the last time; s4, rough polishing, namely spreading polishing cloth on a polishing machine, uniformly smearing first diamond polishing paste, polishing until only shallow scratches remain on the surface of a sample, and adding a small amount of distilled water in the rough polishing process; S5, fine polishing, namely uniformly smearing a second diamond polishing paste, continuously adding distilled water to the surface of the polishing sample until the surface is mirror-shaped, and then washing and drying; s6, preparing electrolyte, namely preparing anhydrous ethanol and perchloric acid into a mixed solution according to the sequence of addition, standing until the solution reaction is completed after the preparation is completed, and cooling to room temperature; And S7, electropolishing, namely setting parameters of the electropolishing machine to be 25V, and setting the current to be 1.45A-1.55A for 12S, clamping the anode of the electropolishing machine on the sample, putting the observation surface of the sample into electrolyte after the electrolysis is started, and immediately flushing and drying after the electrolysis is finished.
2. The method for eliminating black spots induced by the electropolishing preparation of EBSD metal samples according to claim 1, wherein if the scratches of the previous mesh cannot be removed in the finish grinding process in step S3, the previous mesh is returned to be reground, and the force applied to the sample decreases as the mesh increases.
3. The method for eliminating black spots induced by the electropolishing preparation of EBSD metal samples according to claim 1, wherein the step S1 is characterized in that an ultrasonic cleaner is adopted for cleaning, specifically, 75% absolute ethanol is added, the temperature is controlled to be 40 ℃, and the cleaning is carried out for ten minutes.
4. The method for eliminating EBSD metal sample electropolishing preparation induced black specks according to claim 1, wherein the step S2 coarse grinding adopts 80 mesh sand paper, the step S3 fine grinding adopts sand paper with the mesh number as low as 100, 200, 500, 800 and 1000 mesh respectively, and distilled water wet grinding is adopted in the fine grinding process.
5. The method for eliminating EBSD metal sample electropolishing to produce induced black specks of claim 1, wherein said step S4 rough polishing comprises a first diamond paste of W2.5 grit size and step S5 fine polishing comprises a second diamond paste of W0.5 grit size.
6. The method for eliminating black spots induced by the electrolytic polishing of the EBSD metal sample according to claim 1, wherein the step S6 is characterized in that the electrolyte is prepared by the concentration of perchloric acid being 50% and the concentration of absolute ethanol being 100% in a volume ratio of perchloric acid to absolute ethanol being 1:9.
7. The method for eliminating EBSD metal sample electropolishing to prepare induced black specks according to claim 1, wherein the rinsing in the step S5 is 75% absolute ethanol, and the rinsing in the step S7 is 99.7% absolute ethanol.

Description

Method for eliminating black spots induced by electrolytic polishing preparation of EBSD metal sample Technical Field The invention relates to the technical field of EBSD sample preparation, in particular to a method for eliminating black spots induced by electrolytic polishing preparation of an EBSD metal sample. Background The key role of EBSD (electron back scattering diffraction) technology is to perform qualitative and quantitative analysis of the microstructure of crystalline materials. The diffraction pattern is detected and analyzed in a scanning electron microscope, so that the crystallographic information of a micro-area on the surface of the material is rapidly obtained, the orientation, the size, the distribution and the phase composition of crystal grains can be accurately represented, the type of crystal boundary can be identified, the deformation and the recrystallization degree can be analyzed, and the method is a powerful tool for researching the problems of material texture, phase change, deformation mechanism, failure analysis and the like. As is well known, the EBSD sample is prepared by sampling, cleaning, rough grinding, fine grinding, rough polishing, fine polishing, electrolytic polishing and observation. However, in the daily EBSD sample preparation process, especially after the electropolishing step, black spots on the surface due to current often appear, which seriously affect the observation, detection and analysis of normal microscopic structures, and become a difficult sample preparation problem to be solved in the scientific research process. Through earlier investigation, no related means are found at present, so that the problems can be solved conveniently and rapidly. Disclosure of Invention The invention aims to provide a method for eliminating black spots induced by electrolytic polishing preparation of an EBSD metal sample, which aims to solve the technical problems in the background technology. In order to achieve the above purpose, the present invention provides the following technical solutions: S1, cutting and cleaning a sample, namely cutting the sample by a wire cutting machine, cleaning the sample in an ultrasonic cleaner, and drying the sample; s2, rough grinding, namely removing a hardening layer generated by wire cutting on a metallographic grinder by adopting sand paper; s3, fine grinding, namely sequentially wet grinding the sample by adopting sand paper with different mesh numbers from low to high, wherein each grinding ensures that the sample rotates 90 degrees, and scratches of the later grinding are covered for the last time; s4, rough polishing, namely spreading polishing cloth on a polishing machine, uniformly smearing first diamond polishing paste, polishing until only shallow scratches remain on the surface of a sample, and adding a small amount of distilled water in the rough polishing process; S5, fine polishing, namely uniformly smearing a second diamond polishing paste, continuously adding distilled water to the surface of the polishing sample until the surface is mirror-shaped, and then washing and drying; s6, preparing electrolyte, namely preparing anhydrous ethanol and perchloric acid into a mixed solution according to the sequence of addition, standing until the solution reaction is completed after the preparation is completed, and cooling to room temperature; And S7, electropolishing, namely setting parameters of the electropolishing machine to be 25V, and setting the current to be 1.45A-1.55A for 12S, clamping the anode of the electropolishing machine on the sample, putting the observation surface of the sample into electrolyte after the electrolysis is started, and immediately flushing and drying after the electrolysis is finished. Further, if the fine grinding process in step S3 cannot remove the scratches of the previous mesh at a high mesh, the process returns to the previous mesh to polish again, and the force applied to the sample decreases as the mesh increases. Further, in the step S1, an ultrasonic cleaner is adopted to clean, specifically, 75% absolute ethyl alcohol is added, the temperature is controlled to be 40 ℃, and the cleaning is carried out for ten minutes. Furthermore, the step S2 coarse grinding adopts 80-mesh sand paper, the number of sand paper adopted in the step S3 fine grinding is respectively 100, 200, 500, 800 and 1000 meshes, and distilled water wet grinding is adopted in the fine grinding process. Further, the first diamond polishing paste in the rough polishing in the step S4 adopts W2.5 granularity, and the second diamond polishing paste in the fine polishing in the step S5 adopts W0.5 granularity. Further, the electrolyte prepared in the step S6 specifically comprises perchloric acid and absolute ethyl alcohol in a volume ratio of 1:9, wherein the perchloric acid concentration is 50%, and the absolute ethyl alcohol concentration of the prepared electrolyte is 100%. Further, the step S5 is performed with 75% ab